1. Technical Field
The present invention relates to a computer system, and more particularly to an improved interface for a computer system.
2. Related Art
The Audio-Codec '97 (AC97) standard is an audio standard for personal computers (PCs) established by a consortium constructed by PC-associated semiconductor manufacturing companies, for examples, Intel Corporation, Analog Device Corporation, Yamaha Corporation, and NS Corporation, etc. This AC97 is a standard for separating analog and digital circuits from each other in order to obtain an improved performance of audio functions. In detail, the AC97 defines the interface between a digital controller (AC97 digital link) connected to the bus of a computer and an analog codec (AC97 analog codec) serving to process analog inputs/outputs. The term codec is short for compressor/decompressor.
The digital controller (hereinafter referred to as an AC97 controller), which is mounted to a main board, may comprise an input/output (I/O) control hub (ICH) chip or ICH2 chip by Intel Corporation, or a south bridge chip by VIA Corporation. The analog codec is mounted to an optional card such as a sound card or a communication card.
Since the chip supporting the AC97 standard interface is internally provided at the main board, the associated computer system can inexpensively achieve both the audio and communication functions only by use of an external analog codec.
An audio modem riser (AMR) card slot is provided at the main board in accordance with the AC97 standard. In addition to the audio modem riser card, a communication and networking riser (CNR) card and an advanced communication riser (ACR) card are known as cards supporting the AC97 standard interface. These communication and networking riser and advanced communication riser cards additionally have a networking function along with the audio and modem functions supported by existing audio modem riser cards. The communication and networking riser and advanced communication riser cards are provided with an analog codec having an audio function and a communication function. This analog codec performs an audio function and a communication (modem or networking) function respectively required in the associated system, in cooperation with an AC97 controller provided at the main board of the system.
Signals respectively transmitted from the above mentioned audio modem riser, communication and networking riser, and advanced communication riser cards to the AC97 controller of the main board are identical because those cards support the same interface, that is, the AC97 standard interface.
However, these three riser cards, all of which support the AC97 standard interface, have different pin arrangements and different pin numbers for the same signal. As a result, the three riser cards have different card shapes.
For this reason, the audio modem riser, communication and networking riser and advanced communication riser cards may be incompatible with one another despite the fact that they use the same analog codecs having the audio and communication functions. For example, communication and networking riser and advanced communication riser cards cannot be used in a main board provided with an audio modem riser card slot, as shown in the following Table 1. Similarly, audio modem riser and advanced communication riser cards cannot be used in a main board provided with a communication and networking riser card slot. Also, the communication and networking riser card cannot be used in a main board provided with an advanced communication riser card slot.
TABLE 1AMR SlotCNR SlotACR SlotAMR CardUsableXUsableCNR CardXUsableXACR CardXXUsable
I have found that it is inconvenient to use a computer system with a main board which is not compatible with different AC97 cards.